1 Field of the Invention
The present invention relates to a connection for a drilling head and, more particularly, to a connection for drilling heads employed in reverse circulation drilling in which the drilling fluid penetrating the annular zone returns the excavation material through the piping. The invention also relates to the method of employing this connection when an annular zone is produced by means of double piping.
2. Description of the Prior Art
There are numerous types of drilling heads: certain being used to obtain plugs of predetermined size, but whatever the type of tool employed, there is always the difficulty of the complete removal of the excavated material resulting from the advancement of the drilling head. Defective disengagement of the excavation material directly beneath the drilling head considerably slows down the advancement of the drilling tool irrespective of the drilling method employed: simple rotation of the tool or a complex rotating, vibrating and stamping movement and irrespective of the drilling fluid employed: pressurized sludge or air.